If you’re a fan of diet soda or other sugar-free products, here’s some information you may want to consider: On July 17, 2023, the International Agency For Research on Cancer, the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) Joint Expert Committee on Food Additives (JECFA) announced that the artificial sweetener aspartame is a possible carcinogen.
Aspartame, marketed under the brand names NutraSweet, Equal, and Canderel, is an artificial sweetener claimed to be 180-200 times sweeter than sugar. Used in more than 5,000 foods and beverages, Aspartame is one of the world’s most widely used artificial sweeteners prominently featured in tabletop sweeteners, sugar-free syrup, sodas and gum, cereals, instant coffee, dairy products and drink mixes.
The IARC classification of aspartame as possibly carcinogenic to humans is not without controversy and a second WHO group, the Expert Committee on Food Additives, did not change its threshold for the daily amount of aspartame it deems safe to consume at 40 mg per kilogram (or 2.2 pounds) of body weight per day) for adults. That is equivalent to the amount in 14 cans of Diet Coke or 75 packets of powdered sweetener.
The evidence linking aspartame to cancer is not strong. Many studies investigating links between cancer and artificial sweeteners have relied on animals (mice), not humans. For example, a study conducted by the Ramazzini Institute (RI), an independent, not-for-profit research laboratory in Bologna, Italy reported in 2006 and 2007 that aspartame causes dose-related increases in malignant tumors in multiple organs in rats and mice. The mice that consumed aspartame were given doses almost four times the weight of the mice.
Following the WHO announcement, the FDA said in a statement that it “disagrees with IARC’s conclusion.” FDA scientists do not have safety concerns when aspartame is used under the approved conditions. A 12-ounce can of diet soda contains 0.18 grams of aspartame. For a 165-pound adult, it takes approximately 21 cans of diet soda to consume the 3.7 grams of aspartame needed to surpass the FDA's 50 mg/kg of body weight ADI of aspartame.
So why did the WHO and FHO publish the concerns about aspartame? The key points are the words “possibly” “limited evidence” and “under approved conditions.” Except for the risk to those with phenylketonuria (a genetic disorder in the phenylalanine hydroxylase gene causing phenylalanine to build up in the body), aspartame is considered a safe food additive. While it is difficult to imagine an adult consuming more than 14 (or 21) cans of soda a day, aspartame is in all processed foods, so drinking multiple sodas along with your coffee sweetener and processed meals is additive. Like all things involving risk, moderation is the key.